Fluid motor



Aug. 1, 1933. c. E. WILKINS ET AL FLUID MOTOR Filed Oct. 2'7, 1930 2 Sheets-Sheet l INVENTOR5,

(@464 C: A4141, MM Raw Wharf ATTORNEYS.

Aug. 1, 1933. c. E, WILKINS ET AL 1,920,285

FLUID MOTOR Filed Oct. 27, 1930 2 Sheets-Sheet 2 Patented Aug. 1, 1933 UNITED STATES FLUID Mo'roa Charles E. Wilkins and Arthur W. Rafferty,

\ Sacramento, Calif.

Application October 27, 1930. Serial No. 491,420.

3 Claims.

Our invention relates to fluid actuated motors for operating hydraulic jacks or rams adapted for lifting purposes or for operating heavy machinery such as presses and the like.

The objects of the invention are to provide an efiicient and powerful motor, actuated by an expansible fluid such as compressed air or steam, for operating the pump of a' hydraulic jack or ram; and to provide a simple and inexpensive valve mechanism for said motor. Other objects and advantages of the invention will become apparent from the following description, which should be read with the understanding that the form, construction, and arrangement of the several parts may be varied, within the limits of the claims hereto appended, without departing from the spirit of the invention as set forth in said claims.

Our invention will now be described fully with reference to the accompanying drawings, where- Fig. 1 is a vertical central section of a-preferred form of our apparatus.

Fig. 2 is ahorizontal section on the line 2-2 of Fig.1. a

Fig. 3 is a side elevation as'seen of Fig. 1.

Fig. 4 is a vertical sectional detail enlarged, illustrating the valve mechanism and the exhaust valve holding means.

- In the drawings, the reference numeral 1 designates a base, upon which is secured a cylinder 2 having an open upper end. A ram 3 is slidably mounted in said cylinder. The upper and lower ends or heads 4 and 5 of said ram are closed, and its interior is hollow, forming a chamber 6 for the storage of the oil or other lifting fluid used in the device. The lower head 5 carries suitable packing, shown as a cup leather 7, below which is a retaining washer 8 provided with a flange 9,

from the right adapted for contact with the base 1, to act as a stop for the downward stroke of the ram.- Suitable packing 10 is provided at the upper end of the cylinder 2.

The base 1 also carries a pump adapted to withdraw the fluid from the storage or reservoir chamber 6 of the ram and to force it under pressure into the lower portion of the cylinder 2, to lift said ram. The pump comprises a valve head or block 11, suitably secured upon the base 1, and

I upon which is mounted a barrel 12. A plunger 13 is slidably mounted in said barrel. A suitable packing gland, indicated at 14, is provided upon the upper end of the barrel 12. This gland is provided with a space 14a for packing, below which is an annular'chamber 14b adapted to catch any fluid leaking past the plunger 13. A conduit 14c returns said fluid from the chamber 14b to the inlet of the pump.

The pump withdraws oil from the reservoir chamber 6 of the ram, through pipes 15 and 16, a check valve 17 and a passage 18 in the valve head 11. The pipe 15 is carried in the ram itself and therefore moves with it. The pipe 16 is stationary, and a suitable flexible connection, here illustrated, for example, asa hose 19, connects said two pipes. The piunp forces the fluid out of its barrel 12, through a check valve 20 and a passage 21 in the base, into the lower end of the cylinder 2.

In order to prevent leakage of oil around the outside of the ram 3, we provide a circumferential. groove 22 near its lower end, and said groove is connected by passages 23 and a check valve 24 with the interior reservoir chamber 6 of the ram. Thus any oil which leaks past the cup leather 7 is caught by the groove 22 and returns to the storage chamber 6 through the passages 23. The upper head 4 of the ram is provided with an air vent 25, and also prefer-- ably with a screen 26 to prevent splashing of the oil and its escape through said air vent.

When the apparatus is used as a lifting jack, it is preferably provided with a lifting foot 27, positioned low enough to enable it to be placed under objects near the ground. As a preferred means for mounting said foot 27, we have shown it as extending outwardly from a sleeve 28, surrounding the cylinder 2 and provided at its upper end with an inwardly turned flange 29 secured between the head 4 and a shoulder 30 formed upon the ram 3. The lower end of the sleeve 28 is provided with a ring 31 adapted to slide upon the exterior surface of the cylinder 2. Suitable friction reducing rollers, indicated at 32 in Fig. 2, may be provided in the portion of the bearing ring 31 on the side of the foot 27. A spline 33 is preferably provided upon the outside of the cylinder 2 for cooperation with a keyway 34 in the bearing ring 31, to prevent turning of the ram within its cylinder. The side of the sleeve 28 nearest the pump-is cut away, as indicated at 35, to allow it to pass over the suction pipe 19, and the base 1 is preferably cut out at 36 to receive the foot 2'7 when in its lowermost position.

Although any suitable means may be employed for operating the pump plunger 13, such for example as the well known manually operated mechanism commonly employed in hydraulic power operated motor. A preferred form of such power device is illustrated in Figs. 1, 2 and 3, and :omprises a fluid actuated reciprocating motor whose piston is connected directly with the plunger 13. venient pressure fluid may be used, and is introduced through a connection 37, Fig. 3, leading into a valve body 38, in the upper portion of which is mounted a control or shut off valve 39, preferably of the tapered plug type as indicated. From the control valve 39 a pipe 40 leads to a valve chamber 41 formed in the head 42 of a cylinder 43 surrounding the pump plunger 13 and secured to the valve base 11 of the pump. A piston of any suitable form, as indicated at 44, is secured on the upper end of the pump plunger 13, and reciprocates within the cylinder 43. The valve chamber 41 contains an inlet valve 45, through which the air or other actuating fluid is admitted by means of a passage 46 to the cylinder 43, to move the piston 44 and'the pump plunger 13 downwardly. A spring 4'1, housed within the cylinder 43, is employed to return said piston to its uppermost position. The cylinder head 42 carries an exhaust valve 48 controlling passages 49 for the exhausting to the atmosphere of the air from within the cylinder 43 upon the upward stroke of its piston.

The intake and exhaust valves 45 and "48 are operated by a lever 50 whose end lies between the extremities of. the stems of said valves, as shown, and which is connected by a link 51 with a trip 52, adapted to be engaged by the piston 44 at the lower limit of its travel. Thus when said piston descends under the expansive force of the air entering through the inlet valve 45, it strikes and moves the trip 52, thereby swinging the lever 50 and causing the exhaust valve 48 to open and the inlet valve 45 to close. The air supply being thereupon cut off by the closed inlet valve 45, and the pressure within the cylinder being relieved by the openingof the exhaust valve 48, the spring 47 returns the piston upwardly. when said piston reachesthe upper end of its stroke it strikesl the head of the open exhaust valve 48, thereby closing 'it and opening the inlet valve 45. In order to insure the positive operation of the exhaust valve 48 and to prevent it from dropping into the cylinder 43, we provide its stem with two adjacent grooves 53 adapted for engagement by a spring pressed latch 54 as shown in Fig. 4. Thus when the air control valve 39 is opened, the piston 44 reciprocates within its cylinder, operating the plunger 13 of the hydraulic pump and forcing the oil from the storage chamber 6 into the cylinder 2 of the ram.

Obviously the check valve 20 of the pump will hold the ram in any elevated position upon the cessation of operation of the pump. In order to permit the downward return of the ram we provide a valve, indicated at 55 in Figs. 2 and 3, which, when opened, allows the oil to flow from the pres sure conduit 21 in the base through a pipe 56 into the suction pipe 16. from which it returns to the reservoir chamber 6. We also provide a pressure indicator or gauge 57, Fig. 3,*connected with the pressure conduit 21 in the base. This gauge is preferably provided with two scales, as indicated at 58, one of which is calibrated to read in terms of the total pressure exerted by the ram, thus providing an accurate and prompt indication of the weight lifted thereby. The other scale may be the customary one reading in pounds per square inch of oil pressure.

jacks, we greatly prefer to use some form of Compressed air or any other con- .the ram cylinder 2.

In order to enable the ram 3 to be raised quickly when there is comparatively little weight upon it, as for example when adjusting it to position initially, or when lifting shoring blocks or timbers preparatory to exerting the full lifting force, we provide means for admitting the air or other pressure fluid, used to operate the motor, directly to For this purpose the valve body 38, Fig. 3, has a second valve 59 in its lower portion, which, when open, admits air from the supply pipe 37 directly to the pressure conduit 21 in the base and thence to the ram cylinder 2. A check valve 60, in the lower end of the valve body 38, prevents any return flow to the air supply pipes. Thus, if it be desired to raise the ram. 3 quickly against. comparatively little resistance, the valve 59 is opened and the air enters the ram cylinder from the supply pipe 37. It is discharged from said cylinder, when desired, through the relief or return valve 55, passing through the pipes 56, 16 and 15, and through the oil reservoir 6, escaping finally through the vent 25.

In order to prevent the ram from being blown entirely out of the cylinder 2 when operated by the direct air lift described above, -we provide a relief port 61, Fig. 1, in the side of said cylinder near itsupper end. This port connects through a check valve 62 with the return'pipe 16. Thus when the ram is elevated by direct air pressure from the supply pipe 37 until its bottom uncovers the relief port 61, the air escapes through said port and the pipes 16 and 15 into the reservoir 6 and thence out through the vent 25, thereby preventing the ram 3 from being raised further.

We claim:--

1. A fluid actuated motor for the described purpose comprising a cylinder having an inlet and an adjacent outlet; a piston operable therein; a pair of oppositely disposed independent poppet valvescontrolling -said inlet and outlet, each valve having a head and a stem and said valves being shifted in one direction by contact between the head of one of them and said piston at one end of its stroke; means for releasably holding one of said valves in open and closed positions; an operating member positioned between the stems of said valves for engagement with both; and means connected with said operating member and contacted by said piston at the other end of its stroke for shifting said valves in the other direction.

2. A fluid actuated motor for the described purpose comprising a cylinder having an inlet and an adjacent outlet; a piston operable therein; a pair of oppositely disposed independent poppet valves controlling said inlet and. outlet, each valve having a head and a stem, and said valves being shifted in one direction by contact between the head of one of them and said piston at one end of its stroke; means for releasably holdin one of said valves in open and closed positions;

an operating member positioned between the stems of said valves for engagement with both; a trip mounted in the wall of said cylinder and positioned for contact by said piston at the other end, of its stroke; and a connection between said trip and said operating member for shifting said valves in the other direction.

3. A fluid actuated motor for the described purpose comprising a cylinder; a head therefor having a valve chamber communicating with the cylinder, said chamber having a fluid inlet and said head having a fluid outlet; a valve mounted in said chamber for controlling said inlet, said valve having a stem extending through a wall for engagement by said piston at one 'end of its stroke to shift said valves in one direction, said valves being shifted in the other direction by contact between said outlet valve and the piston at the other end of its stroke; and means for releasably holding one of said valves in open and closed positions.

CHARLES E. WILKINS. ARTHUR W. RAFFERTY. 

